AJS & Matchless Owners Club

I've mentioned it elsewhere on this forum but I'll put this all in one topic.
Looking for a better front brake I bought an Enfield interceptor 7" front hub that polished up quite nice.
To fit into it I bought a TLS brake plate from the Indian made singles thinking it would be a straight fit but found its outer diameter larger than the drum - no problem I turned back the drum mouth a little. I also had to remove 1/16th where the plate locates up to the wheel bearing to locate the brake shoes in the right place.
The brake plate has a long boss with a slot in it to locate to the forks - I took this into work and had it welded up and I polished it out.

I turned up a new spindle out of EN16T and a new nut out of some stainless (thanks for the help with the dimensions - see "Wheel Spindle Length) - I'll have a go later at nickle plating the spindles end later (awaiting a anode from fleabay)

Using Lumiweld I added a boss to the brake plate to save having separate spacers - and polished that up.
This paces the hub in the middle of the forks



Cheers
Martin

I've now got to sort out the cam levers, the TLS ones are horrible fabricated and riveted affairs - I could rework them but I need to separate the lever that the cable tugs on from the lever that's connected to the cams as the brake plate is in a different orientation than
on the Enfield so I'm waiting for a cast lever from a 6" hub from India and modify the cam spindle to accept two levers - see my mock up picture - the cable should then sit behind the fork leg with the outer anchored up by the mudguard studs as normal.
I will need to make up a new torgue arm - could anyone tell me how thick they are? - I'll have to rummage to find some material.
I won't be finishing this any time soon but I'll keep this updated.
Cheers
Martin

Hi

With no calculation I would suggest nothing less than 3/16" plate for the torque stay - if you can fit a larger gauge then do so.

Regards Mick

I have just made a torque arm to fit a BSA 8 in single sided brake to my '54 G80. As I said in reply to one of your earlier posts, I made up a new axle in EN16. I used 3/16 in plate, 2 ins wide, from M Metals, Darlington and shaped it by chain drilling and a lot of filing. PM me if you want advice on measuring hole positions. The AMC torque arm was made from thinner stuff (can't remember dimensions) but I based my dimensions on the BSA version which was 1 1/16 ins wide, parallel sides (wider than the AMC version), broadening out to fit the 2 studs on the fork slider. It is also joggled to fit the wider BSA brake, not best engineering practice but that is how BSA did it. Cheers, Andy

Thanks for the replies, I don't suppose it needs to be too thick as it's under tension and not compression where then it would have to resist buckling.
Leaving plenty of meat around the mounting holes will be in order though.

Yep - a "dog bone" shape around the fixing hole is what you need. When these things fail, they let go around or beyond the mounting hole. No need to over-engineer it (though the original AMC shape is a bit marginal for their bigger bikes).

The calculation for how much cross section you need to withstand the tension is pretty easy to do. F=ma, so just plug in the deceleration (0.5g) when fully loaded to get the stopping force, that gives you the force at the tyre edge, then calculate the braking torque to achieve that then work out the resulting force on the arm. Find out the tensile strength of the material and you can work out the minimum cross-section needed. Add a safety margin and you're good to go (or stop).

Mine is just 3mm thick, which works out at 8mm minimum width (I have 10mm).

Here's my torque arm fitted to a Bridgestone TLS hub: As you can see, I haven't got round to making it pretty yet...

clanger9 wrote:....is pretty easy to do. F=ma, so just plug in the deceleration (0.5g) when fully loaded to get the stopping force, that gives you the force at the tyre edge, then calculate the braking torque to achieve that then work out the resulting force on the arm.

Well there's a thing. Cuh! I never realised it was that easy..........

Made up a stainless clevis yesterday for the brake cable.

Very nice. My clevis is ugly bent steel and I haven't found a source of properly made ones.
I don't have the skills & tools to make anything like yours...